Method of preparing asphalt slabs and sheets



Patented Sept. 20, 1927.

UNITED STATES PATENT OFFICE.

METHOD OF PREPARING ASPHALT SLABS AND SHEETSp- No Drawing.

. Asphalt slabs are ordinarily produced by pouring the material over afirm flat surface and passing over the same a heated roller. They arealso produced by shaping them in .5 brick and like. presses. Neither ofthese methods is suitable for the production of very thin sheets. I

The present invention relates to a method whereby ver thin slabs-orsheets of asphalt may be pro uced, and consists in passlng a molten andpartly cooled plastic asphalt sheet between pairs of revolving rollersset successively "more and more close together and dividin the sheetthus produced into l the desired sizes.

For this purpose a'preferably pure mass of asphalt is molten and pouredout so as to form a layer of about 30 millimeters thickness which layeris allowed partly to cool.

Then, while in a plastic state, thelayer 1s passed between pairs ofpress rollers so as to form a .sheet which will be perfectly homogenous,uniform in thickness and smooth on both sides. The number of rollersemployed depends on the desired thickness of the slabs, the rollersbeing set successively more and more close together. Thus, if threepairs of rollers be employed, the first pair may have a spacing of 20,the

second 15, and the third 10 millimeters. By this gradual thinnin of theasphalt it can be reduced to a thic ness of about 3 millimeters, whichis not possible by any of the older methods. .The rolled slabs or sheetsare subsequently cut u into the desired sizes and left to cool w ereuponthey will" retain their shape and be ready for despatch and for aplication. I

.The asp alt can be used in its pure state without the admixture of sandso that very strong and tough asphalt coverings can be obtained by theprocess. After the slabs or sheets have been placed in situ they caneasily be fused toge't or into one continuous surface by means of ablow-lamp or the like. Thus large floors can be laid very quickly andcheaply, the thinness of the covering producing a considerable saving inmaterials. Very thin and cheap floor coverings can be 7 prepared by theimproved method and des- Application filed September 6, 1921. Serial No.498,945.

patched anywhere to be easily laid in situ. The covering need not befixed to the floor and will therefore be independent of the latter andprevent it from cracking and tearing by the expansion and contraction ofthe same. After a considerable period of use, the covering can beremoved from one floor and transferred to another. All kinds of cornersand curves and vertical walls may be covered with asphalt and madewaterproof in this manner. The floor covering can be sup lied ready forapplication and can easily e laid'by anyone without the creation of dustand'evil-smelling fumes. Only half the usual time is required for layingthe floor prepared in this manner. Various articles, such as vessels andthe like, can be made out. of the rolled asphalt plates.

I- am well aware that the formin of plasthe thickness of the sheet andsmoothing the same on both sides thereof until the desired thickness ofthe same is obtained, whereupon the sheet is out up into the,desired'sized slabsor plates.

v 2. The method of forming asphalt plates and slabs consisting inheating and pouring a substantially pure mass of asphalt to form a sheetof about 33 mm.s thickness, then allowing the sheet to partially cool toa plastic state, and then gradually and in successive steps reducing thethickness of thesheet by pressing the same until a thickness of about 3mm. s is obtained, whereu n the sheet is cut into the desired sized sabs and plates.

F. C. J. on BOTH.

